Enhanced adsorption and photodegradation of rhodamine B by BiFeO3 nanoparticles functionalized yeast composite: Synthesis, performance, and mechanism

Dye contaminants from textile and printing industries can cause severe water pollution. Low cost, high removal efficiency, and good regeneration properties are thus highly required for the employed adsorbents in the water treatment process. In this work, for the first time, we report the fabrication of BiFeO₃ nanoparticles functionalized commercial baker's yeast (BiFeO₃–yeast) as one of the effective biological adsorbents with excellent photocatalytic regeneration activity for rhodamine B (Rhd B) removal in static batch and dynamic column two conditions. The successful synthesis of composited BiFeO₃–yeast was characterized by different instruments including SEM, EDS, XRD, TGA, FT-IR, and XPS. Effects of various adsorption conditions, such as adsorption time, environmental temperature, and initial Rhd B concentration were evaluated thoroughly. The BiFeO₃–yeast composite displays a higher Rhd B adsorption capacity (59.42 mg/g) than unmodified yeast (20.47 mg/g), and its monolayer adsorption process has mainly attributed to the combination of physical and chemical interactions. It is also shown that BiFeO₃–yeast possesses good adsorption-photodegradation and recyclability under visible light (<20 % of adsorption capacity lost after four adsorption-desorption cycles). FT-IR and XPS analysis combined with adsorption-photodegradation tests demonstrate that generated surface oxygen-containing functional groups in alkaline hydrothermal synthesis conditions and introduced photocatalyst BiFeO₃ nanoparticles synergistically participated in the adsorption-photodegradation of BiFeO₃–yeast composite for Rhd B. The column test further evidence that BiFeO₃–yeast is effective in the removal of Rhd B in flow condition. Overall, results show that the composited BiFeO₃–yeast is promising for dye removal through adsorption-based photodegradation.